diff_min = 10000 # int value for which different int objects are used.

class C(object):

    desc = ("C.__eq__() implemented with equality of x",
            "C.__ne__() returning NotImplemented")

    def __init__(self, x=None):
        self.x = x

    def __str__(self):
        return "C(%s)" % (self.x,)

    def __hash__(self):
        return self.x

    def __eq__(self, other):
        res = self.x == other.x
        print("C.__eq__(): self=%s, other=%s, returning %s" % (id(self), id(other), res))
        return res

    def __ne__(self, other):
        print("C.__ne__(): self=%s, other=%s, returning NotImplemented" % (id(self), id(other)))
        return NotImplemented

class D(object):

    desc = ("D.__eq__() implemented with inequality of x",
            "D.__ne__() returning NotImplemented")

    def __init__(self, x=None):
        self.x = x

    def __str__(self):
        return "C(%s)" % (self.x,)

    def __hash__(self):
        return self.x

    def __eq__(self, other):
        res = self.x != other.x
        print("D.__eq__(): self=%s, other=%s, returning %s" % (id(self), id(other), res))
        return res

    def __ne__(self, other):
        print("D.__ne__(): self=%s, other=%s, returning NotImplemented" % (id(self), id(other)))
        return NotImplemented


def test_eq(obj1, obj2, txt):
    print("")
    print(txt+":")

    print("  obj1: type=%s, str=%s, id=%s" % (type(obj1), str(obj1), id(obj1)))
    print("  obj2: type=%s, str=%s, id=%s" % (type(obj2), str(obj2), id(obj2)))
    print("  a) obj1 is obj2: %s" % (obj1 is obj2,))

    try:
        res = obj1 == obj2
    except Exception as exc:
        res = "Exception: %s" % (exc,)
    print("  b) obj1 == obj2: %s" % (res,))

    try:
        res = [obj1] == [obj2]
    except Exception as exc:
        res = "Exception: %s" % (exc,)
    print("  c) [obj1] == [obj2]: %s" % (res,))

    try:
        res = {obj1:'v'} == {obj2:'v'}
    except Exception as exc:
        res = "Exception: %s" % (exc,)
    print("  d) {obj1:'v'} == {obj2:'v'}: %s" % (res,))

    try:
        res = {'k':obj1} == {'k':obj2}
    except Exception as exc:
        res = "Exception: %s" % (exc,)
    print("  e) {'k':obj1} == {'k':obj2}: %s" % (res,))

    try:
        res = obj1 == obj2
    except Exception as exc:
        res = "Exception: %s" % (exc,)
    print("  f) obj1 == obj2: %s" % (res,))



def main():
    
    i1 = 257
    i2 = (i1 + i1) // 2
    assert(i1 is not i2)
    
    test_eq(i1, i2, "1. Different equal int objects")
    test_eq(i1, i1, "2. Same int object")

    f1 = 257.0
    f2 = (f1 + f1) / 2
    assert(f1 is not f2)
    
    test_eq(f1, f2, "3. Different equal float objects")
    test_eq(f1, f1, "4. Same float object")

    nan1 = float('nan')
    nan2 = float('nan')

    test_eq(nan1, nan2, "5. Different float NaN objects")
    test_eq(nan1, nan1, "6. Same float NaN object")

    c1 = C(256)
    c2 = C(256)

    test_eq(c1, c2, "7. Different objects (with equal x) of class C\n   (%s)" % (",\n    ".join(C.desc),))
    test_eq(c1, c1, "8. Same object of class C\n   (%s)" % (",\n    ".join(C.desc),))

    d1 = D(256)
    d2 = D(256)

    test_eq(d1, d2, "9. Different objects (with equal x) of class D\n   (%s)" % (",\n    ".join(D.desc),))
    test_eq(d1, d1, "10. Same object of class D\n   (%s)" % (",\n    ".join(D.desc),))


if __name__ == '__main__':
    main()